<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8"/>
        <title></title>
        <style type="text/css">
            #p1 {font-weight: lighter;}
            #p2 {font-weight: normal;}
            #p3 {font-weight: bold;}
            #p4 {font-weight: bolder;}
        </style>
    </head>
    <body>
        <p id="p1">字体粗细为:lighter</p>
        <p id="p2">字体粗细为:normal</p>
        <p id="p3">字体粗细为:bold</p>
        <p id="p4">字体粗细为:bolder</p>
    </body>
</html>